The present invention relates to micro-mechanical electrical systems (MEMS) type device for measuring vibration and movement, and more particularly to a MEMS accelerometer.
MEMS type devices for use as sensors and accelerometers are well known. Such devices are generally fabricated on a silicon or related planar substrate by semi-conductor manufacturing type methods, such as the use of photo-resists, masks and various etching processes to fabricate a proximity sensor that includes a suspended proof mass member and means to measure the deflection of the proof mass suspending means. Such devices have inherent limitations on the minimum size, detection limit, sensitivity and the like, largely due to the means used for detecting the deflection of the proof mass.
It is therefore a first object of the present invention to provide 3-dimensional capacitive accelerometer that could be fabricated using a single process.
Yet a further objective is to provide maximum capacitive sensitivity with minimum packaged size of the accelerometer. Obtaining this objective enable a highly efficient accelerometer that provides maximum response with minimum power demands.
It is still a further object of the invention to provide a means to combine multiple accelerometers in a configuration for the simultaneous measurement acceleration in three dimensions.
It is a further objective to provide such a 3-dimensional accelerometer that can be used in cardiovascular applications for example, in a linear structure that is easy for fabrication and packaging in a lead or catheter.